They flop and slip and make sweet love on the sand under the full moon’s light.

Grunion — unique little fish found only in Southern California and down south in Baja — are little marine critters that mate on the sand when the waves wash them to shore. When the grunion are running, people in the know show up in the dark of night to wait and watch, some ready with buckets to collect the critters to eat, when catching them is allowed.

A male grunion wraps around a female as she lays thousands of eggs during the highest of tides at Doheny State Beach. Grunion activity happens from March to August on the second, third and fourth days after a full moon. SCNG FILE PHOTO

Thousands of grunion come ashore to lay and fertilize their eggs at Doheny State Beach. Grunion activity happens from March to August on the second, third and fourth days after a full moon. SCNG FILE PHOTO

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Thousands of grunion come offshore to lay and fertilize their eggs after a new and full moon at Doheny State Beach from March through August. SCNG FILE PHOTO

Grunion greeters came out in large numbers to observe the mating ritual of the small critters at Doheny State Beach. SCNG FILE PHOTO

Scott Seagull, left, and, Corey Shore run free at Doheny State Beach trying to see who can catch the most grunion during a run a few years ago. SCNG FILE PHOTO

FISH OUT OF WATER: A few grunion were washed ashore to the delight of Sammi Scotto a few years ago at Doheny State Beach. A few dozen people waited desperately to see the grunion running. SCNG FILE PHOTO

A group of grunion make their way back toward the water after spawning on the shore at Doheny State Beach. SCNG FILE PHOTO

A group of male grunions crowd around a female who has buried herself in the sand at at Doheny State Beach. SCNG FILE PHOTO

Quoc Tran, of Westminster, displays a handful of grunions that he caught around midnight during a grunion run a few years ago During their mating season, grunions swim onto the shore, making them an easy catch for birds and fisherman alike.. SCNG FILE PHOTO

Dana Point resident Rory Ingram gets a photo of a grunion with the camera on her cell phone, during Doheny State Beach’s 20th Annual “Grunion Night” a few years ago. Photo: David Bro/For The Orange County Register

A lone female grunion wiggles back toward the water after laying eggs on the shore at Doheny State Beach. SCNG FILE PHOTO

Billy Le, of Garden Grove uses a headlamp to help him spot grunions at Seal Beach a few years ago. SCNG FILE PHOTO

“It’s a cool California thing,” said Jim Serpa, who for 20 years ran a grunion night at Doheny State Beach while he was supervising rangers, before retiring a few years ago.

The grunion season officially kicked off early March, and the next run is expected Saturday, March 17 through Tuesday, March 20.

So grab your flashlights, beach chairs and, if you don’t mind staying up late, get ready to watch them run.

Serpa offered tips on why they run, the best times to go, and interesting tidbits about the fascinating fish:

1. Why do grunions wash up on shore?

They are mating. They have to mate at night, when the tide is at its highest around a full moon. They want to be on the sand so the eggs have a long time to incubate, Serpa said. They live off shore when they are not running — they just don’t come to shore unless it’s spring or summer.

Each female lays 2,000 to 3,000 eggs. They have a short life — only about five years max — and get to be about six inches long. The females bury themselves up to the fins, deposit their eggs and the males deposit the milt right there. When the wave comes by, the sand closes it up. The eggs stay buried in the sand for 10 to 14 days. The wave and surge jostling helps them hatch.

2. Find a beach they like

Some beaches, they don’t run on. It all depends on what’s underneath, if it’s good sand, Serpa said. They don’t like gravelly beaches. You might not see them in one spot, but a mile farther, they might be going like gangbusters. At Doheny, it’s rocky underneath but once you get on the beach, it’s sand. It’s perfect for them.

“When I was growing up, we always went to La Jolla. Any beach like that — Huntington, Crystal Cove and there’s a great beach up by the Cabrillo Aquarium in San Pedro. Malibu would be a great beach for it,” he said. “You want a beach that is a real gradual, you don’t want a shore break beach where the waves drop and dump.” Serpa said they seem to like Doheny, perhaps because the jetty acts as a shelter. Cabrillo offers something similar.

3. Go early in the season

They always run really good in the early part of the season, in April and May, Serpa said. As we get further into the year, it’s more hit or miss.

April and May, however, is the closed part of the season — so it’s just for watching, no catching.

4. Don’t spook the scouts

Try and let them come up and start their full run before you start annoying them and shining bright lights on them. “I don’t know that there’s been any real scientific data on it, but what we noticed, they always run better if you start letting them run for a while,” Serpa said.

5. Know the tides

You always want to go right before the peak of the high tide. They don’t run until that peak happens, Serpa said. If they do run before that, they have a chance of their eggs washing out.

“A lot of people, they see the run at midnight and say ‘let’s go at 10,'” Serpa said. “Kids are waiting and two hours later they haven’t run and they say, ‘let’s get out of here.'” The good time is the peak and the people just came too early. Timing is critical.

6. Watch the birds

“We would go out an hour or two before the peak of the high tide,” Serpa said. “If the birds were lined on the beach waiting, that means the grunions were in the shallows and they are ready to run and (the birds) know it.”

7. Tips for taking

You’ll need a fishing license if you are 16 or older. And don’t take anything you won’t use. You can only take with your hands — no scooping devices. That allows for more grunion to go back and helps the resources to stay healthy, Serpa said.

8. Don’t get soaked

Keep your eyes on the waves, Serpa warned. People get so absorbed with picking up the grunions, and then the wave comes and they get soaked.

9. Are they tasty?

If you ask me, I’d say no, Serba said. “But plenty of people like them,” he said. “A lot of people fry them up, the whole thing. Other people gut them.”

10. Fishing is good during grunion runs

Local fishermen know that. There’s halibut during that time, Serpa said. He’s seen huge halibut taken off the beach during grunion run nights.

11. Are the waters sharkier during grunion runs?

Nobody has done a study on that, Serpa said, but putting two and two together, it might be a good guess. “Juvenile sharks love grunion,” he said. “So offshore might be a place to see (sharks).”

12. What should we bring to a grunion run?

A flashlight, chair so you can sit while you’re waiting, a bucket to put your grunion in and a fishing license if you are planning to take them. A jacket to stay warm is always a good idea.

Laylan Connelly started as a journalist in 2002 after earning a degree in journalism from the University of Southern California. Through the years, she has covered several cities for The Orange County Register, starting as a beat reporter in Irvine before focusing on coastal cities such as Newport Beach, Dana Point and Laguna Beach. In 2007, she was selected for a prestigious Knight New Media fellowship focusing on digital media at UC Berkeley, where she learned skills to adapt to the ever-changing online landscape. Using a web-based approach, she turned her love for the ocean into a full-time gig as the paper’s beaches reporter. The unique beat allows her to delve into coastal culture by covering everything from the countless events dotting the 42 miles of coastline, to the business climate of the surf industry, to the fascinating wildlife that shows up on the shores. Most importantly, she takes pride in telling stories of the people who make the beaches so special, whether they are surfers using the ocean to heal, or the founders of major surf brands who helped spawn an entire culture, or people who tirelessly fight to keep the coast pristine and open for all to enjoy. She’s a world traveler who loves to explore the slopes during winter months or exotic surf spots around the globe. When she’s not working, or maybe while she's researching a story, you can find her longboarding at her favorite surf spots at San Onofre or Doheny.

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